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Yellow stains at solder lines?


#1

It sounds as if the student has used a low carat solder. I think we
need a little more about how it was made, pickled and
polished.

Tony Konrath
Gold and Stone
http://www.goldandstone.com


#2
    It sounds as if the student has used a low carat solder. I
think we need a little more about how it was made,
pickled and polished. Tony Konrath 

The piece is a link bracelet made with sterling wire, each link
soldered, then hammered flat. Since it was made in a classroom
setting it was probably pickled in community pickle, rinsed in water
with baking soda. Then she filed and sanded but had not polished.
She was going to next try tumbling in steel shot with burnishing
compound.

The solder used is what the classroom there provides – from a local
Chicago supplier.

Elaine Luther
Chicago area, Illinois, USA
Certified PMC Instructor
@E_Luther


#3

While solder lines can be detected - even after burnishing, I’d
still suspect that the solder used was not plumb solder - possibly it
was “easy” which does sometimes have a yellowish cast to it. In
communal settings the care that most of us take to keep our solders
separate and easily identified gives way in the final moments of
class as everyone rushes to put tools and materials away!

The solution is to finish it to the final polish and then send it
away (or do it in-house if you have the equipment) for a heavy silver
electroplating.

Tony Konrath Gold and Stone http://www.goldandstone.com


#4

Sounds to me like just typical solder lines. If the seam is not
absolutely tight, you’ll get a line such as this. In contrast to
the white of the silver (PMC), the solder will appear somewhat
yellow do to the brass (copper and zinc) constituent of the solder.

Andy C.


#5

Elaine,

There are at least 100 different silver solder formulas. Some of

them are quite yellow in color next to sterling. Most of the time
jewelry supply companies do not sell the yellow ones to us but
welding supply companies will have the yellow ones. I think it might
be possible that the solder is the cause of the yellow color. Was it
an easy or extra easy one? These tend to be the most yellow .

Jim –